The present invention relates to an epoxy resin low electronic impedance high molecular weight polymer.
In the existing high molecular weight polymer series, there is yet no high molecular weight polymer which can be co-polymerized and cross linked with a resin monomer and hardened to form an electrically conductive polymer. Especially, when applied to epoxy resin floor coatings, the epoxy resin itself is an insulating material having excellent insulation, voltage-resistance, electric induction, etc. Generally, the volume resistance coefficient thereof is between 1012-1017 (xcexa9xc2x7cm). In order-to achieve a staticproof or even anti-explosion property, the volume resistance coefficient of the epoxy resin must be lowered to  less than 108 (xcexa9xc2x7cm). With respect to the existing technique level, generally, conductive metal particles, carbon black powder, interface activating agent ion crystallized particles, electroplating metal short fibers, etc. are added to the epoxy resin main agent to serve as another kind of filling agent of the epoxy resin. Such filling agent itself fails to participate in the cross linking reaction between the epoxy resin high molecular weight polymers. The current is conducted by means of the contact between the molecular particles of the conductive filling agent. The conductive filling agent does not react with the epoxy resin to crosslink the epoxy resin so that the formed epoxy resin conductive floor layer has numerous defects. For example, the basic physical properties of the epoxy resin are ruined, mechanical strength is deteriorated, working technique is limited, etc. Most seriously, the resin itself not only is not conductive, but also will block the continuity of the current of the conductive filling agent. Therefore, the conductivity is unstable and the conductive floor will gradually lose its conductivity after being worn.
In this high technology time, the electronic and chemical industries have become more and more developed and advanced. Various automatic production equipment is used at high efficiency and speed. This leads to the problem of static. Especially, in the field of the semiconductor industry, the static will result in damage to the electronic circuit of the semiconductor and attachment of great amount of micro-dusts. As a result, a dustless room will be seriously contaminated. In the case that an excessively great amount of static is stored, a static discharging spark may take place. When encountering a combustible or explosive gas, a tragedy of gas explosion may take place. Therefore, the conductive epoxy resin floor plays an important role in the field of industrial factory floor.
With the above background, according to the present invention, the high molecular weight polymer as a non-filling agent directly participates in the cross linking reaction between the epoxy resin polymeric molecules and is copolymerized therewith and hardened to form a two-liquid type cross linking reaction thermosetting engineering plastic. Such plastic has excellent conductivity and is able to fully keep the common physical, chemical and mechanical properties, acid/alkali-resistance, weather-resistance, polish, and long using life of the original epoxy resin. In other words, the plastic is a high molecular epoxy resin polymer with low electronic impedance. More importantly, when applied to pavement to provide a conductive floor coating, not like the conductive filling agent product series which is greatly limited in working technique and method, the high molecular weight epoxy resin polymer c a n be applied according to the conventional working method of the epoxy, resin to achieve the desired objects. Doubtless, the epoxy resin conductive floor coating series of the present invention can be used instead of the existing epoxy resin conductive floor coating series made of conductive filling material. Thus, the serial products of the present invention can be entirely commercialized, popularized and specified.
As mentioned above, the up-to-date technical level of conductive and anti-static high molecular weight polymers is limited to adding a conductive filling agent and there is yet no conductive or anti-static high molecular weight polymer directly participating in the reaction. With respect to the currently collected references, for example, Taiwanese Patent No. 105227 entitled xe2x80x9cconductive resin compoundxe2x80x9d, a resin compound is disclosed, which contains (1) 25-99.5 weight % of isomerized polymer and (2) 0.5-75 weight % of conductive mineral black. It is mentioned in this reference that the resin can be co-used with other xe2x80x9cconductive filling materialsxe2x80x9d. The so-called xe2x80x9cconductive filling materialsxe2x80x9d means metal micro-particle series such as graphite powder, silver powder, copper powder, nickel powder, stainless steel powder, tin dioxide powder, copper/silver mixture powder, nickel/silver mixture powder, silver-painted glass ball, copper gas ball, etc., metal fragment series such as aluminum fragment, bronze fragment, nickel/iron alloy fragment, etc., and metal short fibers including carbon fiber, aluminum fiber, bronze fiber, aluminum strip, cold-plated fiber glass, carbon-painted fiber glass, etc. It can be known from the above description that xe2x80x9cconductive filling materialsxe2x80x9d in fact do not go through a polymerization reaction with the high molecular polymer. Furthermore, it is clearly shown from the comparison table disclosed in the reference that when A/B/C/D four kinds of resins are free from any conductive filling material, the measured volume resistance coefficients are all above 1016 xcexa9xc2x7cm. Therefore, it can be proved that the resin itself is a high molecular weight polymer which is totally not conductive.
In addition, in Japanese Patent Publication. No. 2-2904 entitled xe2x80x9cconductive floorxe2x80x9d, a conductive floor painting material is disclosed, which is composed of colored compound resins which are hardened at normal temperature. The compound resins such as epoxy resin, unsaturated polyester resin, etc. are mixed with conductive filling materials such as zinc white powder, aluminum micro-particle, etc. The mixture is co-used with fiber-like reinforcing materials such as carbon fiber, stainless steel fiber, fiber glass, etc. and anti-abrasion metal bone material (stainless steel micro-particles). No conductive polymerization or reaction related to the resin is seen from the description of the reference. This reference merely describes what kind of conductive filling material is added and how the filling material is added to achieve better conductive function. Therefore, it is still concluded that the high molecular weight resin itself is not conductive and substantially insulating.
The interesting thing is that the description mentions that the conductive floor material has a viscosity within a range from 4000 to 13000 cps and thus has a good fluidity. Therefore, a so-called xe2x80x9cplane flowing floor surface working methodxe2x80x9d can be achieved as a break through of the working method. However, this can only achieve a plane surface and versatile colors for selection. The problems of xe2x80x9cmirror face polishxe2x80x9d and xe2x80x9cfilm thicknessxe2x80x9d of working are not mentioned. This further proves the fact that the high molecular resin basically is not conductive.
Furthermore, in Taiwanese Patent Publication No. 343987 entitled xe2x80x9canti-static resinxe2x80x9d, an anti-static resin compound is disclosed, which is composed of 5-50% hydrophilic copolymer and 50-95% thermoplastic resin. In fact, the hydrophilic copolymer is polymerized by means of self-emulsification polymerization method and pertains to one kind of anti-static interface activating agent. Such anti-static agent is better than a general one. However, basically, it is also a kind of conductive filling material. When blended with ABS resin, it is clearly shown from the table that the lowest resistance coefficient among all the embodiments is only 7xc3x97109. The others are all above 1010. The electronic impedance of the surface of the formed product is still considerably high. Therefore, such material can be hardly qualified as a conductive additive of the thermosetting resin floor painting. In other words, a practical purpose cannot be achieved by means of adding such conductive filling agent to the conductive floor painting.
Japanese Patent Nos. 165559 and 36297 disclose an application of a kind of metal electroplating short fiber as a conductive filling material. These Patents focus on a painting method for epoxy resin conductive floor. The materials used include 1. carbon fiber mesh (a conductive fiber matting formed by carbon fiber); 2. electroplating alloy short fiber; 3. various kinds of metal scales (mainly copper, aluminum and stainless steel); and 4. various kinds of epoxy resin liquids. However, the resin itself is not conductive so that a great amount of conductive filling material must be added thereto to achieve a satisfactory conductivity. Basically, once the conductive carbon fiber matting is mixed into the non-conductive laminated resin, the conductive function will be immediately deteriorated and it is necessary to further add metal short fiber thereto for enhancing the conductivity. Accordingly, the material cost is increased and the working time is greatly prolonged. Moreover, the greatly added conductive filling materials will make the surface of the floor dim. In addition, the micro-particles of the filling materials will be oxidized and detached to become powder dust. This not only leads to pollution, but also tends to cause unidentified sparks due to abrasion. Therefore, such paint is full of potential danger and not idealistic.
In order to obviate the above problems, according to the present invention, a high molecular weight polymer with low electronic impedance is co-polymerized with an epoxy resin to form a resin liquid which itself has good and stable conductivity. Therefore, the inconvenience and waste caused by greatly adding the conductive filling materials are avoided. The resin liquid can be used as a general epoxy resin floor coating or paint. With respect to the fiber laminate, the laminated epoxy resin liquid co-polymerized with the low electronic impedance high molecular weight polymer of the present invention itself has the conductive function. Therefore, the non-conductive fiber glass matting (GRF) is immediately changed into a xe2x80x9ccomplex conductive FRP laminate materialxe2x80x9d with excellent conductivity. This is another characteristic of the present invention.
It is a primary object of the present invention to provide an epoxy resin high molecular weight polymer with low electronic impedance. This can be described in view of two respects. First is related to the description of the intermediate body of the low electronic impedance high molecular weight polymer. The second is related to the description of the participation of the intermediate body in the co-polymerization of the epoxy resin to form the conductive low electronic impedance high molecular weight epoxy resin polymer. With respect to the preparation of the intermediate body of the low electronic impedance high molecular weight polymer, a metallic salt is mixed with a certain amount of inorganic acid and fully stirred to dissolve and form a metallic ion solution. Then an alcohol is added into the solution to go through a secondary dehydration and form a complex ion polymer with double bonds and n electrons. Such polymer is in an acidic environment so that it will continuously react and polymerize. Therefore, it is necessary to first neutralize the acidic environment of polymer to maintain the pH within a range of 6xcx9c8 so as to terminate the reaction. This is the preparation procedure of the intermediate body of the low electronic impedance high molecular weight polymer. In general, the best way to neutralize the acidic environment is to add a certain amount of amine so as to reach a neutralized pH and terminate the reaction of the polymer and change the polymer into a stable and usable material.
With respect to the co-polymerization between the intermediate body of the low electronic impedance high molecular weight polymer and the epoxy resin for forming the low electronic impedance epoxy resin polymer, it is applicable to those thermosetting engineering plastic products, painting films or laminated complex materials related to epoxy resin, such as civil engineering series: antistatic epoxy resin floor and conductive anti-static spark and anti-explosion floor; wall-used painting series: operating room anti-static floor, ceiling and wall face painting, anti-static painting for the surface of plastic cases of electric appliance; laminated complex material series: anti-acid/alkali barrel or reservoir laminate, anti-electromagnetic wave interference laminated painting for wall face, floor, outer wall of roof, etc. With respect to the co-polymerization of the low electronic impedance high molecular weight polymer intermediate body with the epoxy resin, with the normal temperature two liquid-type epoxy resin floor pavement material exemplified, the description is as follows: during stirring of the epoxy resin (bisphenol A series), the low electronic impedance high molecular weight polymer intermediate body (ensure that pH is within 6xcx9c8) is added thereto so as to totally dissolve both. Then a color paste and various necessary aids specifically used for the conductive epoxy resin are added to form a complete major agent mode of the conductive floor coating. Then a cross linking bridging reaction hardener with a weight of 5-50% of the epoxy resin major agent is taken to be fully evenly stirred with the epoxy resin major agent. Thereafter, the mixture is painted on the surface of a painted article to form a coating film or poured into a mold to form a cast model body after being hardened and demolded. This is the low electronic impedance high molecular weight polymer. During the cross linking reaction, the low electronic impedance high molecular weight polymer intermediate body plays an important conducting role. The resonance of the double bonds and n electrons contained by itself as well as the inter-winding between the molecular structure of the formed product form a current path to achieve the conductive function.
The present invention can be best understood through the following detailed description: